A variable optical attenuator including: a birefringent element positioned
to separate an input optical signal into two spatially separated,
orthogonally polarized beams; a LC modulator positioned to receive the
orthogonally polarized beams and selectively alter their polarizations; a
reflective element positioned to reflect the beams back through the LC
modulator and the birefringent element, wherein the birefringent element
recombines orthogonally polarized components of the reflected beams to
produce an output optical signal; and a controller coupled to the LC
modulator to selectively cause the LC modulator to alter the polarizations
of the orthogonally polarized beams, wherein during operation the
controller is responsive to a request to variably attenuate the intensity
of the output optical signal relative to the intensity of the input
optical signal to one of multiple non-zero attenuation settings.
